Subject: General Aptitude · Chapter: Average · Exam: 2005 · Marks: · Difficulty:
There were 35 students in a hostel. If the number of the students is increased by 7, then the expenses of the mess increase by ₹ 42 per day, while the average expenditure per head diminishes by ₹ 1 . The original expenditure of the mess per day was
(a)₹ 400
(b)₹ 420
(c)₹ 432
(d)₹ 442
Answer
Answer (as printed): B
Explanation
Let the original expenditure of the mess per day be ₹ $x$. Then, new expenditure $=₹(x+42)$. $$\begin{aligned} & \therefore \frac{x}{35}-\frac{(x+42)}{42}=1 \\ & \Rightarrow 6 x-5(x+42)=210 \\ & \Rightarrow x-210=210 \\ & \Rightarrow x=420 . \end{aligned}$$
Explanation as extracted from the printed page; notation may be imperfect.